Crypto(仿射密码解密)

此密文是通过函数y=5x+12得到的

def affine(a, b):
    pwd_dic = {}
    for i in range(26):
        if i+65 >=65 & i +65 <=90:
            pwd_dic[chr(((a * i + b) % 26) + 65)] = chr(i + 65)
        if i+97 >=97 & i +97 <=122:
            pwd_dic[chr(((a * i + b) % 26) + 97)] = chr(i + 97)
    return pwd_dic
if __name__ == '__main__':
    pwd_dic= {}
    pwd1 = 'RgYDMllakzGc'
    plain = []
    pwd_dic = affine(5, 12)
    for i in pwd1:
        plain.append(pwd_dic[i])
    print ('Flag:'+"".join(plain))